Oral chemotherapy agents in the treatment of leukaemia.

Oral chemotherapy agents have been an important component of the treatment of leukaemia for many years. Obstacles such as poor or erratic bioavailability and noncompliance have often limited the utility of oral agents in the treatment of leukaemia. However, recent evaluations of new or existing oral agents have expanded the clinician's options and understanding of the use of these drugs in the treatment of leukaemia. One major advance is the use of tretinoin (all-trans retinoic acid) in the treatment of acute promyelocytic leukaemia (APL). Tretinoin, an oral vitamin A derivative that reverses abnormal differentiation in APL is now an essential component of first-line therapy for APL, replacing standard intravenous chemotherapy induction regimens. Other advances include an increased understanding of the pharmacokinetic and pharmacodynamic profile of oral chemotherapy agents such as etoposide and high dose busulfan, allowing for modifications or individualisation of administration regimens to enhance efficacy or minimise toxicity. Evaluations of noncompliance with oral agents in the treatment of leukaemia have also provided the clinician with important information on how this obstacle to oral therapy may be overcome or minimised.